Mounting for electric lamps



Jan. 23, 1962 E- M. OKEEFE MOUNTING FOR ELECTRIC LAMPS 2 Sheets-Sheet 1Filed Dec. 24, 1959 Jan. 23, 1962 E. M. OKEEFE MOUNTING FOR ELECTRICLAMPS 2 Sheets-Sheet 2 Filed Dec. 24, 1959 United States Patent3,018,366 MOUNTING FOR ELECTRIC LAMPS Eugene l OKeefe, Wauwatosa, Wis.,assignor to Phoenix Products Company, Inc., Milwaukee, Wis., acorporation of Wisconsin Filed Dec. 24, 1959, Ser. No. 861,813 2 Claims.(Cl. 24041) This invention relates to the mounting of electric lamps,and refers more particularly to the mounting of lamps in situationsWhere the lamp is subjected to severe vibration and shock, as, forinstance, the rough service expected of heavy ground Working equipmentused by contractors.

Shock resistant mountings for electric lamps are, of course, not new,and it has been long recognized that a mounting which clasps the lamp byits peripheral portion, i.e. the rim of its lens, and thereby floatinglysupports the lamp from its housing assures longer lamp life than one inwhich the lamp is mounted by its base, as for instance by having itsbase screwed into a receptacle or socket.

It has been found, however, that even those mountings which grasped thelamp by its peripheral portion, possessed a heretofore unsuspectedsource of lamp failure, especially where the lamp was of the typeequipped with terminal prongs projecting laterally from a metal shellfitted to the base of the lamp. In these lamps, the leadin wires for theends of the filament are brought out through the base of the lamp andsoldered to the prongs. Since the inner end portions of the prongs towhich the filament lead-in wires are soldered, are inside the metalshell or cap which is fitted to the lamp base, and the prongs must besupported in a way which keeps them electrically insulated from themetal shell, despite the fact that the prongs pass through its sidewall, it follows that the prongs must be capable of easy assembly anddisassembly with their support. This requirement is met by seating theprongs rather loosely in pockets or slots formed in a block of ceramicinsulation which, in turn, is loosely nested into the cup-shaped metalshell.

To connect the lamp with a source of current, its prongs are pluggedinto a suitable socket or receptacle which is flexibly connected, insidethe housing of the lamp, to the end of the supply cord. For twoimportant reasons, the socket or receptacle is not secured to thehousing. If it were, it would interfere with the floating mounting ofthe lamp; and also, to enable plugging in the lamp, it must be possibleto withdraw the socket or receptacle from the housing.

Because of the manner in which the prongs have to be mounted, it isinevitable that they are free to vibrate with respect to the lamp baseand the metal shell fitted thereon, and since the prongs constitute theonly support for the receptacle into which they are inserted, the weightor mass of the receptacle aggravates the ill effects of freedom of theprongs to vibrate or move relative to the lamp base.

It is this vibration or movement of the prongs with respect to the lampbase which has beenfound to cause breakage of the filament lead-in wiresor their soldered connections to the terminal prongs.

Having discovered this source of lamp failure, it would appear that theremedy, would lie in a redesign of the lamp to eliminate the possiblevibration of the terminal prongs relative to the lamp base. Though thismight be done, it still would not solve the problem.

Bearing in mind that the receptacle or socket by which the prongs are,of necessity, tightly gripped, adds its weight and mass to that of theprongs, and that the socket or receptacle cannot be supported from thefixture housing without nullifying the cushioning efiect gained by theshock resistant lamp mounting, it follows that ICE while the prongsmight be initially secure against vibratory motion relative to the lampbase, they would soon loosen.

Moreover, a redesign of the lamp might very well result in a loss ofsome of the advantages of the lamp as it now exists, and might entail aneconomically unwarranted increase in its cost of production. The problemto which this invention is directed, therefore, assumes that the lampmust be accepted in its existing form, with the terminal prongs free tovibrate with respect to the lamp base.

It is, therefore, the purpose and object of this invention to providesimple means by which relative vibratory motion between the prongs andthe lamp base may be eliminated, without requiring any change in thestructure of the lamp.

This invention achieves this purpose in an extremely expeditious way, bythe simple expedient of securing the receptacle against vibratory motionwith respect to the lamp base.

With the above and other objects in View which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate one complete example of thephysical embodiment of the invention constructed according to the bestmode so far devised for the practical application of the principlesthereof, and in which: a 7

FIGURE 1 is a side view of a light fixture of the type with which thisinvention is concerned, having part thereof broken away; 7

FIGURE 2 is a front view of the fixture;

FIGURE 3 is a perspective view of the lamp and its terminal receptacle,shown separated;

FIGURE 4 is a view of the lamp and its receptacle in assembled relation;7

FIGURE 5 is a view partially in side elevation and partially inlongitudinal section, through the lamp and its receptacle;

FIGURE 6 is a view partially in side elevation and partially in section,on the plane of the line 6-6 in FIG- URE 5; and 7 FIGURE 7 is aperspective view of the terminal prong assembly of the lamp shownseparated from thelamp,

Referring now more particularly to the accompanying drawings, thenumeral 8 designates the housing of alight fixture of the type withwhich this invention is primarily concerned, and which serves as amounting and enclosure for an electric lamp 9. The housing 8 issupported between the arms of a yoke 10 which, in turn, has aswivelledconnection to a base 11 securable to any supporting structure. a

The lamp 9 is readily removably mounted in the housing 8 by a shockresistant mounting which grasps the lamp by its peripheral portion 12.While this shock resistant mounting for the lamp forms no part of thisinventiomit must be understood that whatever means are employed to somount the lamp in the housing has to permit the lamp to be removed forreplacement, and must support the lamp in a way which precludes, or atleast greatly minimizes, the transmission of shock and vibration fromthe lamp housing to the lamp.

The lamp is a standard product made by one of the larger manufacturersof electric lamps, and comprises a glass envelope 13 composed of a rearreflector section and a front lens section. The lamp filament 14 issupported in the envelope by a pair of rods or filament supportingelements 15 which project forwardly from the base 16 of the lamp, asbest seen in FIGURE 6. The filament supporting elements or rods 15 maybe embedded directly in the glass base 16 but, preferably, are mountedin the manner illustrated in Patent No. 2, 194,373, issued to GeneralElectric Company, March 19, 1940. Accordingly, the filament supportingelements or rods 15 are secured in small metal caps 17 which, in turn,ar sealed to the glass base.

Preferably the filament lead-in wires 18 are wrapped about thesupporting elements or rod 15 and have their outer ends exposed on theexterior of the caps 17 or electrically connected thereto. In any event,they are connected with terminal prongs 19 by short lengths of wire 18.

The prongs 19 extend edgewise across the flat rear face of the lampbase, With their outer end portions 2%}, which are doubled back uponthemselves-or hairpin-shaped projecting laterally beyond the base. Theprongs are held in this position by a block 21 of insulating material,preferably ceramic which, in turn, is secured in position by acup-shaped metal shell or cap 22 tightly fitted to the base of the lamp.

The block 21 of insulating material is of a size and shape to fill themajor part of one-half of the cup-shaped shell and is held in thisposition by being confined between the rear of the lamp base and the endwall 24 of the shell and between the side wall 25 of the shell and themetal caps 17. A boss 26 on the block of insulating material projectsthrough a hole 27 in the side wall of the shell, and by having theterminal prongs nested therein, serves to insulate the same from theshell.

The securement of the shell 22 to the lamp base is effected by engagingthe shell over the base and pressing diametrically oppositie portions 28of the side wall of the shell into correspondingly located pockets ornotches in the lamp base. To facilitate snug engagement of the shellwith the lamp base, its side wall 25 has diametrically opposite slits 29therein, preferably equispaced between the indented portions 28.

Although the described assembly fairly well secures the block ofinsulation 21 against movement with respect to the lamp base and shell22, it does not hold the prongs 19 against vibratory motion with respectto these parts. This follows from the fact that, to enable the describedassembly and particularly to enable the terminal prongs to be solderedto the terminal portions of the filament lead-ins, the mounting of theprongs in the block of insulation 21 inevitably leaves the prongs ratherloose.

Thus, as clearly shown in FIGURE 7, the medial portions of the prongsare received in slots 30 formed in the block of insulation, the slotsbeing wide enough to freely receive the prongs therein and the depth ofthe slots being such that the prongs will be loosely confined edgewisebetween the back of the lamp base and the bottom of the slots.

In the endwise direction, the prongs are loosely held againstdisplacement by shoulders 31 formed therein as a result of offsettingtheir inner ends, and by the abutment of the ends of the inturned outerend portions with the adjacent face of the boss 26.

Though the described construction of the lamp and the mounting of itsprongs forms no part of this invention, it has been detailed toillustrate the problem with which this invention is concerned.

As noted hereinbefore, lamps constructed in this manner have advantagesover other available lampsas, for instance, those which use a screw typeconnection with their sockets or receptacles. These advantages are wellunderstood in the art, but, as pointed out hereinbefore, they also havea disadvantage which was not heretofore recognized-namely, that theinevitable looseness of the terminal prongs led to relative vibratorymotion between them and the terminal portions of the filament lead-inwires and this, in turn, caused breakage of the lead-in wires, or theirsoldered connections to the prongs.

With the present invention, this objection is entirely eliminated by thesimple expedient of securing the receptacle 35 into which the terminalprongs are engaged to connect the lamp with a current source, againstrelative motion with respect to the lamp base and the metal shell 22.

The receptacle 35 is of conventional construction and consists of a bodyof insulating material, preferably made up of two complementary halves,held together by a bolt 36. Opening to one of its faces, this block ofinsulating material has a pair of sockets 37 into which the terminalprongs are snugly and tightly received. Inside these sockets are thefemale connectors (not shown) of the receptacle, which, as is wellunderstood, are connected with conductor leads 38. The conductor leads38 are flexible and long enough to allow the entire receptacle to bewithdrawn from the lamp fixture housing 8, despite the fact that theconductors are connected to the supply cord 39 which, in turn, isanchored to the housing at its point of entry thereinto.

As indicated, the prongs 19 tightly fit the sockets 37, so that whenthey are engaged therein, the prongs, for all intents and purposes,become anchored to the receptacle or, stated conversely, the receptacleis supported by the prongs. Hence, by securing the receptacle againstrelative motion with respect to the lamp base and the shell 22, thepossibility of vibratory motion between the prongs and the terminalportions of the lamp filament is eliminated. V

To hold the receptacle to the lamp base, a U-shaped strap or bail 40 ishingedly connected to the receptacle by means of a bracket 41 fixed tothe receptacle by the bolt 35, and pivotally connected with the ends ofthe U-shaped strap or bail, as at 42. The bight or closed end of thebail has a nut 43 fixed thereto, in which a clampin screw 44 isthreaded.

As clearly shown in FIGURE 4, the bail 40 is of a size to embrace themetal shell when the lamp prongs are plugged into the receptacle and,upon tightening of the screw 44 the receptacle will be drawn tightlyagainst the boss 26 of the insulating block 21, to thereby hold theentire assembly firmly together and against relative vibratory motion ofits several parts.

From the foregoing description, taken in connection with theaccompanying drawings, it will be readily apparent to those skilled inthis art, that this invention overcomes an objection inherent in anelectric lamp and its manner of mounting or connecting the same to anelectric supply which, though heretofore not recognized, has beennonetheless experienced to a large degree and unjustly charged to orconsidered a defect in a lamp which has many advantages and which isvery well suited to use in situations where the fixture in which thelamp is located is subjected to extreme vibration and shock.

What is claimed as my invention is:

1. In combination: an electric lamp having a glass envelope with anintegral glass base, filament leads entering the envelope through theglass base and having ends disposed externally of the base, a metalshell tightly fitted to the exterior of the glass base and enclosing theexternal ends of the filament leads, terminal prongs for the lamp, meansmounting said prongs with their inner ends inside the metal shell andtheir outer end portions outside the shell, and in a manner which leavesthem free to vibrate with respect to the shell and the glass base, andmeans physically and electrically securing the prongs to said externalends of the filament leads; a receptacle having sockets in which theprongs are tightly received, and by which the prongs are connectiblewith current supply lines; and clamping means carried by the receptacleand engaging the metal shell remote from the receptacle to draw thereceptacle against the shell and thereby secure the receptacle as wellas the prongs and their connections to said external ends of thefilament leads against vibratory motion with respect to the shell andthe glass base. 2. The combination of claim 1, wherein the shell iscup-shaped and the terminal prongs pass through one side wall portion ofthe shell; and further characterized by the fact that said clampingmeans comprises a bail hingedly connected to the receptacle andembracing the shell, and screw means carried by the bail and reactingagainst the opposite side wall portion of the shell.

References Cited in the file of this patent UNITED STATES PATENTSMcFaddin Mar. 24, 1914 Piercy Oct. 24, 1933 Douglas Oct. 2, 1934 GrossMay 16, 1950 Arnejo Mar. 26, 1957

